U.S. patent application number 15/095118 was filed with the patent office on 2017-10-12 for drive shaft press.
The applicant listed for this patent is Toyota Motor Engineering & Manufacturing North America, Inc.. Invention is credited to Robert D. McClain, Keith J. Wells.
Application Number | 20170291269 15/095118 |
Document ID | / |
Family ID | 59999468 |
Filed Date | 2017-10-12 |
United States Patent
Application |
20170291269 |
Kind Code |
A1 |
Wells; Keith J. ; et
al. |
October 12, 2017 |
DRIVE SHAFT PRESS
Abstract
A simplified drive press system is operable to press fit a pair
of first working pieces into a second work piece. The drive press
system uses a simplified mechanical arrangement to translate an
input torque into movement of a pair of drive arms toward and away
from one another. Yokes of differing configurations may be attached
to the drive arms to accommodate a variety of different work
pieces. A nut runner may be used to supply a drive torque to the
gear assembly and provide a controlled input torque and control the
movement of the drive arms. An overall reduction may be utilized
that balances a desired movement resolution with the desire to
detect changes in input torque. The nut runner may be programmable
to provide a desired movement of the drive arms while monitoring
the input torque to detect when a fully press-fitted condition is
realized.
Inventors: |
Wells; Keith J.;
(Evansville, IN) ; McClain; Robert D.; (Haubstadt,
IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Toyota Motor Engineering & Manufacturing North America,
Inc. |
Erlanger |
KY |
US |
|
|
Family ID: |
59999468 |
Appl. No.: |
15/095118 |
Filed: |
April 10, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23P 19/02 20130101;
F16H 2048/382 20130101; F16H 48/38 20130101; F16H 2057/0043
20130101; F16H 57/023 20130101 |
International
Class: |
B23P 19/02 20060101
B23P019/02; F16H 48/38 20060101 F16H048/38; F16H 57/023 20060101
F16H057/023 |
Claims
1. A press system comprising: at least one moveable rack, the at
least one rack being operatively connectable with a first work
piece and operable to move the first work piece relative to a
second work piece, the at least one rack having a plurality of gear
teeth; a mechanical drive system operable to move the at least one
rack and a connected first work piece relative to the second work
piece, the drive system including a gear assembly operatively
coupled to the at least one rack and an input member operatively
coupled to the gear assembly, rotation of the input member driving
rotation of the gear assembly; and a nut runner operatively
connectable to the input member, the nut runner operable to supply
a drive torque to the input member to drive movement of the at
least one rack and press fit the first and second work pieces
together.
2. The press system of claim 1, wherein the gear assembly and at
least one rack provide a resolution of about 1 inch of travel for
between 10 to 100 revolutions of the input member.
3. The press system of claim 2, wherein the gear assembly and at
least one rack provide a resolution of about 1 inch of travel for
about 50 revolutions of the input member.
4. The press system of claim 1, wherein the at least one rack is a
pair of moveable racks that are each operable to engage with a
different work pieces and move relative to one another with
rotation of the input member.
5. The press system of claim 4, wherein the gear assembly includes
an input gear rotating with rotation of the input member and a
reduction gear engaged with the input gear such that rotation of
the input member drives rotation of the reduction gear.
6. The press system of claim 5, wherein the gear assembly includes
a drive gear rotating with rotation of the reduction gear, the
drive gear being engaged with the racks such that the drive gear
drives movement of the racks due to rotation on the input
member.
7. The press system of claim 6, wherein the input gear and the
drive gear have a same number of gear teeth.
8. The press system of claim 5, wherein a gear ratio between the
input gear and the reduction gear is between about 2:3 and about
1:20.
9. The press system of claim 1, wherein the nut runner is a
programmable nut runner.
10. The press system of claim 1, wherein the at least one rack
moves about 0.1 inch for each revolution of the input member.
11. A mechanical press system comprising: a pair of moveable racks,
the racks have a plurality of teeth and operable to move toward and
away from one another to press-fit first work pieces engaged with
the racks into a second work piece which is stationary relative to
the racks; a removable yoke associated with each rack, the yoke
operable to engage with one of the first work pieces and drive
movement of the first work piece with movement of the rack; a
mechanical drive system operable to move the racks, the drive
system including a gear assembly operatively coupled to the racks
and an input member operatively coupled to the gear assembly,
rotation of the input member driving rotation of the gear assembly
which drives movement of the racks; and a nut runner operatively
connectable to the input member, the nut runner operable to supply
a drive torque to the input member to drive movement of the racks
and press fit the first and second work pieces together.
12. The press system of claim 11, wherein the gear assembly
includes an input gear rotating with rotation of the input member
and a reduction gear engaged with the input gear such that rotation
of the input member drives rotation of the reduction gear.
13. The press system of claim 12, wherein the gear assembly
includes a drive gear rotating with rotation of the reduction gear,
the drive gear being engaged with the teeth of the racks such that
the drive gear drives movement of the racks due to rotation on the
input member.
14. The press system of claim 13, wherein rotation of the drive
gear in a first direction drives movement of the racks towards one
another and rotation of the drive gear in a second direction
opposite the first direction drives movement of the racks away from
one another.
15. The press system of claim 14, wherein the input gear and the
drive gear have a same number of teeth.
17. The press system of claim 15, wherein a gear ratio between the
input gear and the reduction gear is between about 2:3 and about
1:20.
18. The press system of claim 11, wherein the gear assembly and the
racks provide a resolution of about 1 inch of travel for between 10
to 100 revolutions of the input member.
19. The press system of claim 18, wherein the gear assembly and the
racks provide a resolution of about 1 inch of travel for between 10
to 100 revolutions of the input member.
20. The press system of claim 11, wherein each rack moves about 0.1
inch for each revolution of the input member.
Description
FIELD
[0001] The subject matter described herein relates in general to
presses and, more particularly, to a drive shaft press.
BACKGROUND
[0002] Modern vehicles commonly come in a variety of platform sizes
and in a variety of models on a particular platform size. The drive
systems for these vehicles can vary based on the platform, the
model, and the drive configuration (e.g., front wheel drive, rear
wheel drive, and all-wheel drive). These differing drive systems
will have differing drive shafts, differentials, transfer cases,
etc. The drive shafts are typically press fit into the differential
or transfer cases. The press fitting is typically done with press
equipment that is specifically designed for a particular platform,
model and drive configuration. As a result, an assembly plant will
require many different pieces of equipment to meet the press
fitting demands and must coordinate the availability of these
different pieces of equipment with production schedules and
changes.
[0003] Modern press-fitting equipment uses a PLC controlled servo
system to perform the press-fitting operation. The use of PLC
controlled servo systems makes the press-fitting equipment more
complicated. Additionally, PLC controlled servo systems are
expensive and may require a customized program for each vehicle
configuration. As such, the cost to provide for pres-fitting
equipment for an assembly plant that produces a variety of vehicle
configurations can be excessive.
[0004] Accordingly, there is a need for a simplified drive press
system that can be utilized on a variety of vehicle configurations.
Additionally, it would be advantageous if the cost for the drive
press system can be reduced over that of PCL controlled servo
systems.
SUMMARY
[0005] A simplified drive press system is operable to press fit a
pair of first working pieces into a second work piece. The drive
press system uses a simplified mechanical arrangement to translate
an input torque into movement of a pair of drive arms toward and
away from one another. Yokes of differing configurations may be
attached to the drive arms to accommodate a variety of different
work pieces. A nut runner may be used to supply a drive torque to
the gear assembly and provide a controlled input torque and control
the movement of the drive arms. An overall reduction may be
utilized that balances a desired movement resolution with the
desire to detect changes in input torque. A gear ratio may be
between about 2:3 and about 1:20. The gear assembly may provide a
resolution of about 0.1 inch of rack movement per revolution of the
nut runner. The nut runner may be programmable to provide a desired
movement of the drive arms while monitoring the input torque to
detect when a fully press-fitted condition is realized.
[0006] In one respect, the present disclosure is directed to a
press system having at least one moveable rack which is operatively
connectable with a first work piece and operable to move the first
work piece relative to a second work piece. The at least one rack
has a plurality of gear teeth. A mechanical drive system is
operable to move the at least one rack and a connected first work
piece relative to the second work piece. The drive system includes
a gear assembly operatively coupled to the at least one rack and an
input member operatively coupled to the gear assembly. Rotation of
the input member drives rotation of the gear assembly. A nut runner
is operatively connectable to the input member. The nut runner
supplies a drive torque to the input member to drive movement of
the at least one rack and press fit the first and second work
pieces together.
[0007] In another respect, the present disclosure is directed to a
mechanical press system having a pair of moveable racks. The racks
each have a plurality of teeth and are operable to move toward and
away from one another to press-fit first work pieces engaged with
the racks into a second work piece which is stationary relative to
the racks. There is a removable yoke associated with each rack.
Each of the yokes engages with one of the first work pieces and
drives movement of the first work piece with movement of the rack.
A mechanical drive system is operable to move the rack. The drive
system includes a gear assembly operatively coupled to the racks
and an input member operatively coupled to the gear assembly.
Rotation of the input member drives rotation of the gear assembly
which drives movement of the racks. A nut runner is connectable to
the input member and is operable to supply a drive torque to the
input member to drive movement of the racks and press fit the first
and second work pieces together.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is perspective view of an exemplary simplified
mechanical press system.
[0009] FIG. 2 is a side view of the press system of FIG. 1.
[0010] FIGS. 3 and 4 are perspective views of the press system of
FIG. 1.
[0011] FIG. 5 is bottom view of the press system of FIG. 1.
[0012] FIG. 6 is an end side view of the press system of FIG.
1.
[0013] FIGS. 7 and 8 are side views of the press system of FIG. 1,
showing an exemplary pair of drive shafts and a differential in an
initial position and an assembled position, respectively.
DETAILED DESCRIPTION
[0014] This detailed description relates to a simplified drive
press system operable to press fit a pair of first working pieces
into a second work piece. The drive press system uses a simplified
mechanical arrangement to translate an input torque into movement
of a pair of drive arms toward and away from one another. Yokes of
differing configurations may be attached to the drive arms to
accommodate a variety of different work pieces. A nut runner may be
used to supply a drive torque to the gear assembly and provide a
controlled input torque and control the movement of the drive arms.
An overall reduction may be utilized that balances a desired
movement resolution with the desire to detect changes in input
torque. A gear ratio may be between about 2:3 and about 1:20. The
gear assembly may provide a resolution of about 0.1 inch of rack
movement per revolution of the nut runner. The nut runner may be
programmable to provide a desired movement of the drive arms while
monitoring the input torque to detect when a fully press-fitted
condition is realized.
[0015] Detailed embodiments are disclosed herein; however, it is to
be understood that the disclosed embodiments are intended only as
exemplary. Therefore, specific structural and functional details
disclosed herein are not to be interpreted as limiting, but merely
as a basis for the claims and as a representative basis for
teaching one skilled in the art to variously employ the aspects
herein in virtually any appropriately detailed structure. Further,
the terms and phrases used herein are not intended to be limiting
but rather to provide an understandable description of possible
implementations. Various embodiments are shown in the Figures, but
the embodiments are not limited to the illustrated structure or
application.
[0016] It will be appreciated that for simplicity and clarity of
illustration, where appropriate, reference numerals have been
repeated among the different figures to indicate corresponding or
analogous elements. In addition, numerous specific details are set
forth in order to provide a thorough understanding of the
embodiments described herein. However, it will be understood by
those of ordinary skill in the art that the embodiments described
herein can be practiced without these specific details.
[0017] Referring to FIGS. 1-6, an exemplary simplified mechanical
press system 20 is shown. It should be appreciated that in the
views, various components of press system 20 may be omitted to
allow illustration of other components. Press system 20 is
configured and arranged to press work pieces, such as drive shafts,
differentials and transfer cases, together using a controlled input
force. Press system 20 is scalable and may come in various sizes to
accommodate work pieces of differing sizes, shapes and input force
requirements. The scalable nature allows for a standardized
construction to be implemented in an assembly plant to meet the
various production demands and vehicle configurations. The use of
standardized construction may allow for the use of standard input
devices to power press system 20 using the same or modified
programming.
[0018] In one or more arrangements, press system 20 includes a pair
of yokes 22 operatively connected to pair of drive arms 24. Yokes
22 may include fingers 23 that are configured to support work
pieces, such as shown in FIGS. 7 and 8. Because the work pieces may
come in a variety of shapes and sizes, yokes 22 and fingers 23 may
also come in a variety of shapes and sizes, as needed, to meet the
needs of the particular work pieces. Yokes 22 may be removably
connected to drive arms 24 to allow yokes 22 of differing sizes,
shapes and configurations to be coupled thereto. This allows press
system 20 to accommodate differing work pieces. For example, yokes
22 may be connects to drive arms 24 by threaded fasteners 26 or the
like.
[0019] In one or more arrangements, drive arms 24 may include a
rack 30 having a plurality of teeth 32 thereon. Each rack 30 may be
coupled to a backer plate 34, such as by fasteners 36. Backer plate
34 may provide a rigid structure to support rack 30 and the
press-fitting of the work pieces together. Backer plate 34 may have
opposite main surfaces 38 separated by side surfaces 42. Rack 30
may be coupled to one of the main surfaces 38. Drive arms 24 are
operable to move relative to one another, such as along an X-axis,
which in turn moves yokes 22 toward and away from one another to
press-fit the work pieces together, as described below. The
distance D separating yokes 22 changes as drive arms 24 move along
the X-axis.
[0020] In one or more arrangements, press system 20 includes a base
assembly 46 that may form the structural frame. Base assembly 46
may include a pair of plates 48 and a pair of side members 50 and
spacers 51 extending therebetween and spacing plates 48 apart from
one another, such as along a Y-axis by way of example. Plates 48
may be attached to side members 50 and spacers 51 with fasteners
52, by way of example. Base assembly 46 may enclose (within plates
48 and side members 50) a majority of the mechanical drive system
and components of press system 20.
[0021] In one or more arrangements, drive arms 24 are partially
disposed within base assembly 46 and move relative thereto. A
plurality of cam followers 58 may be coupled to plates 48 within
base assembly 46. Cam followers 58 coupled to each plate 48 may be
spaced apart from one another both along a Z-axis and along the
X-axis, as shown. The spacing of cam followers 58 may form a first
guide channel within which drive arms 24 move. For example, cam
followers 58 may engage with surfaces 38 of backer plate 34 to
guide the movement of drive arms 24 relative to the Z-axis as drive
arms 24 move along the X-axis. Another plurality of cam followers
60 may be coupled to side members 50 within base assembly 46. Cam
followers 60 coupled to each side member 50 may be spaced apart
from one another both along the Y-axis and along the X-axis, as
shown. The spacing of cam followers 60 may form a second guide
channel within which drive arms 24 move. For example, cam followers
60 may engage with side surfaces 42 of backer plate 34 to guide the
movement of drive arms 24 relative to the Y-axis as drive arms 24
move along the X-axis. In this arrangement, cam followers 58, 60
together may guide and limit the movement of drive arms 24 relative
to the Z-axis and Y-axis as drive arms 24 move along the X-axis.
Cam followers 58, 60 may be a bearing with a hardened exterior
surface by way of non-limiting example.
[0022] In one or more arrangements, press system 20 may include a
drive system 70 operable to drive movement of drive arms 24 along
the X-axis. Drive system 70 may include a gear assembly 72
operatively connected to an input member 74 and to drive arms 24.
For example, gear assembly 72 may include an input gear 76 coupled
to input member 74 and engaged with a reduction gear 78 which may
be coupled to a drive gear 80 which may be engaged with both racks
30. Input gear 76 and input member 74 may be locked together such
that they both rotate in unison. For example, input member 74 may
be keyed into input gear 76 such that relative rotation is
prevented and rotation of input member 74 drives rotation of input
gear 76. Reduction gear 78 and drive gear 80 may be locked together
such that they both rotate in unison. For example, reduction gear
78 and drive gear 80 may be fixedly attached or keyed to one
another such that relative rotation is prevented and rotation of
reduction gear 78 drives rotation of drive gear 80. In this manner,
rotation of input member 74 in a first rotational direction drives
movement of drive arms 74 in a first motion toward one another
along the X-axis and rotation of input member 74 in a second
rotational direction, opposite the first rotational direction,
drives movement of drive arms 74 in a second motion away from one
another along the X-axis. Thus, the distance D between yokes 22 may
be altered by rotation of input member 74 and work pieces may be
press-fit together.
[0023] In one or more arrangements, input gear 76, reduction gear
78 and drive gear 80 each has a plurality of teeth around its
perimeter. The number of teeth of each gear 76, 78, 80 and the
number of teeth per inch on rack 30 control the rate of linear
movement of drive arms 24 as a function of the rotation of input
member 74. Input member 74, as discussed below, may be rotated with
a nut runner. The press-fitting of the work pieces together with
press system 20 may be controlled by the gear ratio between input
gear 76 and reduction gear 78, the number of teeth on drive gear 80
and the number of teeth per inch on racks 30 and may allow for
greater resolution of the press-fitting operation. For example, a
gear ratio of less than 1:1 may allow for multiple revolutions of
input member 74 for each increment of linear movement of drive arms
24. The greater the resolution, the greater the control over the
movement of the drive arms 24 and the more precisely the work
pieces may be moved relative to one another by drive arms 24. The
greater resolution, however, may result in less input torque
feedback. Input torque feedback may be beneficial in evaluating the
force imparted in the press-fitting operation and the occurrence of
a change in force required for further linear movement of drive
arms 24. For example, the work pieces may include a snap ring or
other positive engagement feature that engages when a predetermined
relative position between the work pieces occurs. The positive
engagement may result in an increase in resistance to further
relative movement and may correspond to a fully press-fit
engagement between the work pieces. Detection of the increase in
input torque may be indicative of the completion of the
press-fitting operation and serve as a signal to stop further
movement of drive arms 24 toward one another. Rapid detection of
the increased input torque may inhibit or prevent over compression
of the work pieces together by allowing the nut runner operation to
be ceased more quickly. Thus, it may be advantageous to provide a
balance between resolution and input torque change detection.
[0024] In one or more arrangements, press system 20 uses a gear
ratio (the ratio between input gear 76 and reduction gear 78), the
number of teeth on drive gear 80 and the number of teeth per inch
on racks 30 (collectively, the "overall reduction") to balance
between providing increased resolution and input torque change
detection. For example, in one or more arrangements press system 20
may use an overall reduction that provides a resolution that for
each revolution of input member 74 drive arms 24 move less than
about 0.1 inches (about 1 inch of travel for every 10 revolutions).
In one or more arrangements, the overall reduction is selected so
that about 1 inch of movement of drive arms 24 is achieved with
between preferably 10 and 100 revolutions of input member 74 and,
more preferably with about 50 revolutions. As another example, in
one or more arrangements press system 20 may use an overall
reduction that provides for an input torque detection in the range
of about 30-250 Nm per revolution of input member 74. In one or
more arrangements, press system 20 may have a gear ratio of between
about 2:3 and about 1:20. By way of example, input gear 76 may have
20 teeth, reduction gear 78 may have 200 teeth (a 1:10 gear ratio),
drive gear 80 may have 20 teeth and racks 30 may have 20 teeth per
inch thereby providing a resolution of about 0.1 inches of movement
for each rotation of input member 74. Thus, the resolution may be
varied by adjusting the gear ratio, the number of teeth on drive
gear 80, and/or the number of teeth 32 per inch on racks 30.
[0025] In one or more arrangements, a nut runner is used to drive
rotation of input member 74. For example, electric or pneumatic nut
runners available from Atlas Copco, Coretec or other nut runner
companies may be used to drive rotation of input member 74. The nut
runner may provide a controlled input torque and a controlled rate
of rotation. The nut runner may be connected to a controller that
measures the number of revolutions and the applied input torque and
controls the rate of rotation and input torque applied. In one or
more arrangements, the nut runner may be programmed to provide a
desired operation of press system 20. The programming may vary
based on the particular work pieces to be press-fit together. For
example, different work pieces may require a lower or greater input
torque and/or may require less or more travel of drive arms 24 for
full press-fit engagement. As such, various programs may be
provided for a nut runner so that the nut runner and the press
system 20 may be used with work pieces having differing
press-fitting needs/requirements. The controller may also record
the press-fitting operation and the parameters of the nut runner to
provide a record of the press-fitting operation.
[0026] In one or more arrangements, as shown in FIGS. 7 and 8,
press system 20 is configured to press-fit a pair of drive shafts
90 into a differential 92. For example, drive shafts 90 may each be
coupled to a yoke 22 with fingers 23 engaged with complementary
grooves or recesses of drive shafts 90 and ends 94 aligned with
openings in differential 92. Yokes 22 may engage with drive shafts
90 and push drive shafts 90 into differential 92. For example,
fingers 23 may push on a shoulder or rib 96 on drive shafts 90 to
drive movement of drive shafts 90 into differential 92 and
press-fit drive shafts 90 to differential 92. In use, differential
92 is placed in a holder/rack (not shown) and drive shafts 90 are
arranged in yokes 22 with fingers 23 adjacent shoulder 96 and ends
94 aligned with corresponding openings on differential 92. If
needed, input member 74 is rotated to move drive arms 24 to
accommodate the placement of differential 92 and drive shafts 90.
Once in position, input member 74 may be rotated in a direction
corresponding to drive arms 24 moving toward one another which will
cause ends 94 to enter into the corresponding openings in
differential 92. For example fingers 23 of yokes 22 may push on
shoulders 96 of drive shafts 90 to drive movement of drive shafts
90 into differential 92. As explained above, a nut runner may be
used to drive rotation of input member 74. Input member 74
continues to be rotated until drive shafts 90 are fully fitted
within differential 92. The fully fitted condition may be detected
by a change in the required input torque on input member 74 to
continue rotation in the press-fitting direction. It should be
appreciated that during the press-fitting operation and prior to
being in the fully press-fit position, the required input torque to
drive movement of drive arms 24 may increase as a function of
distance traveled. The detection of the fully press-fit position
takes into account the possibility of increasing input torque
required prior to the fully press-fit condition being realized and
may also take into account the distance traveled by drive arms 24.
After the fully press-fit condition is realized, the nut runner
will cease rotating input member 74. The cessation may be
automatic. After the fully press-fit position is realized, input
member 74 may be rotated in an opposite direction, if needed, to
remove loading between yokes 22 and the work pieces and allow the
work pieces to be removed from press system 20.
[0027] It will be appreciated that arrangements described herein
can provide numerous benefits, including one or more of the
benefits mentioned herein. For example, arrangements described
herein may provide simplified mechanical press system 20 that may
accommodate a variety of work pieces. Press system 20 may use a
commercially available nut runner that can measure the input torque
and the number of revolutions and control the same to press-fit
work pieces together in a controlled and recordable manner. The nut
runner program may be configured for the particular work pieces.
The use of a simplified mechanical press and a programmable nut
runner may allow for a lower cost press system 20 that may
accommodate a variety of work piece configurations and
press-fitting requirements.
[0028] The terms "a" and "an," as used herein, are defined as one
or more than one. The term "plurality," as used herein, is defined
as two or more than two. The term "another," as used herein, is
defined as at least a second or more. The terms "including" and/or
"having," as used herein, are defined as comprising (i.e. open
language). The phrase "at least one of . . . and . . . ." as used
herein refers to and encompasses any and all possible combinations
of one or more of the associated listed items. As an example, the
phrase "at least one of A, B and C" includes A only, B only, C
only, or any combination thereof (e.g. AB, AC, BC or ABC). The term
"operatively connected" as used throughout this description, can
include direct or indirect connections, including connections
without direct physical contact.
[0029] Aspects herein can be embodied in other forms without
departing from the spirit or essential attributes thereof.
Accordingly, reference should be made to the following claims,
rather than to the foregoing specification, as indicating the scope
of the invention.
* * * * *